2012 Annual Report
1a.Objectives (from AD-416):
The objective of this research is to characterize trait variation of the USDA-ARS Vitis germplasm collections. The phenotypic trait information collected from this study, in combination with the genotypic information generated from the grape SNP discovery project led by Dr. Ed Buckler at ARS, will significantly advance our knowledge and capability in identifying useful allelic variation in the Vitis germplasm for grape improvement. In addition, one mapping population relevant to winegrape breeding will also be characterized to examine how well the research results of trait variation from Vitis germplasm can be extended to practical breeding material.
1b.Approach (from AD-416):
Phenotype USDA-ARS Vitis germplasm collections:
1. Phenotyping berry shape, berry color, berry length and width, and cluster size per Standard Biodiversity International Descriptors for all non-hybrid Vitis germplasm accessions (about 700) from the USDA-ARS Geneva Vitis Clonal Repository. This work will be closely coordinated with the ongoing phenotyping effort at the USDA-ARS Davis Vitis Clonal Repository and the ARS grape SNP discovery project of Dr. Ed Buckler et al.
2. Analyzing key primary and secondary metabolites of 600 Vitis germplasm accessions from the USDA-ARS Vitis Clonal Repositories at Davis, CA and Geneva, NY. A total of 3,600 samples (3 replicates x 2 years x 600 accessions) will be analyzed.
Phenotype one mapping population relevant to winegrape breeding:
1. Analyzing key primary and secondary metabolites of the Horizon x Illinois 547-1 mapping population developed by Dr. Bruce Reisch at Cornell. A total of 400 samples (2 replicates x 2 years x 100 lines) will be analyzed.
Analyze phenotypic data and carry out marker-trait association analysis:
1. Characterizing properties of the phenotypic trait variation investigated.
2. Collaborating with Dr. Ed Buckler and his group to carry out marker-trait association analysis.
3. Validating association analysis results with linkage mapping data.
The objective of this project is to characterize the genetic variation of key secondary metabolites, polyphenols in particular, in the berry samples of USDA-ARS Vitis collections maintained in the Clonal Repositories in Davis, California and Geneva, New York. Polyphenols are an important group of secondary metabolites with significant nutrition and health benefits to humans. The compositions and contents of polyphenols, to a large extent, determine the quality of grape berry, juice and wine.
In the past few years, we had characterized the profiles of polyphenols in both cultivated and wild grape species preserved in the USDA-ARS Vitis clonal repositories in Davis, California and Geneva, New York. We continued this characterization work for Vitis hybrids in 2011. The composition and content of polyphenolic compounds in the berries of 48 Vitis hybrids were characterized. A total of 48 polyphenolic compounds including 28 anthocyanins, 2 hydroxybenzoic acids, 6 hydroxycinnamic derivatives, 6 flavonols and 6 flavanols were identified via HPLC-MS and quantified by HPLC-DAD. As expected, the content of total polyphenols as well as individual polyphenolic compounds varied significantly among hybrids and the relative abundance of these compounds in the hybrids were generally between the parental species of hybrids. A number of hybrids with high content of total polyphenols and various individual groups of polyphenolic compounds were identified. This work will contribute to our continued effort for establishing a database of health-related compounds for the Vitis germplasm we preserve in the USDA-ARS repositories.
We have also determined the composition and content of polyphenolic compounds in the berries, flesh and peels of 13 red flesh Vitis accessions. The content of total polyphenols ranged from 4.795 to 29.875 mg g-1 FW in berries, from 1.960 to 12.593 mg g-1 FW in flesh, and from 17.067 to 60.182 mg g-1 FW in peels. Anthocyanins were the main polyphenolic compounds, which accounted for 90.4, 89.4 and 94.1% of the total polyphenols in berry, flesh and peel, respectively. Flavanols accounted for 36.2, 35.3 and 38.3% of the non-anthocyanin polyphenols, flavonols accounted for about 11.6, 5.7 15.8% of the non-anthocyanin polyphenols, hydroxycinnamic derivatives accounted for 53.8, 56.1 and 44.3% of non-anthocyanin polyphenols and hydroxybenzoic acids accounted for 1.5, 3.0, 1.9% of non-anthocyanin polyphenols in berry, flesh and peel, respectively. Knowing the range of content variation of polyphenols in these red flesh grapes is a significant step in using them for breeding red flesh grapes in the future.